Merge tag 'block-ioctl-cleanup-5.6' into 5.6/scsi-queue

Pull compat_ioctl cleanup from Arnd. Here's his description:

This series concludes the work I did for linux-5.5 on the compat_ioctl()
cleanup, killing off fs/compat_ioctl.c and block/compat_ioctl.c by moving
everything into drivers.

Overall this would be a reduction both in complexity and line count, but
as I'm also adding documentation the overall number of lines increases
in the end.

My plan was originally to keep the SCSI and block parts separate.
This did not work easily because of interdependencies: I cannot
do the final SCSI cleanup in a good way without first addressing the
CDROM ioctls, so this is one series that I hope could be merged through
either the block or the scsi git trees, or possibly both if you can
pull in the same branch.

The series comes in these steps:

1. clean up the sg v3 interface as suggested by Linus. I have
   talked about this with Doug Gilbert as well, and he would
   rebase his sg v4 patches on top of "compat: scsi: sg: fix v3
   compat read/write interface"

2. Actually moving handlers out of block/compat_ioctl.c and
   block/scsi_ioctl.c into drivers, mixed in with cleanup
   patches

3. Document how to do this right. I keep getting asked about this,
   and it helps to point to some documentation file.

The branch is based on another one that fixes a couple of bugs found
during the creation of this series.

Changes since v3:
  https://lore.kernel.org/lkml/20200102145552.1853992-1-arnd@arndb.de/

- Move sr_compat_ioctl fixup to correct patch (Ben Hutchings)
- Add Reviewed-by tags

Changes since v2:
  https://lore.kernel.org/lkml/20191217221708.3730997-1-arnd@arndb.de/

- Rebase to v5.5-rc4, which contains the earlier bugfixes
- Fix sr_block_compat_ioctl() error handling bug found by
  Ben Hutchings
- Fix idecd_locked_compat_ioctl() compat_ptr() bug
- Don't try to handle HDIO_DRIVE_TASKFILE in drivers/ide
- More documentation improvements

Changes since v1:
  https://lore.kernel.org/lkml/20191211204306.1207817-1-arnd@arndb.de/

- move out the bugfixes into a branch for itself
- clean up scsi sg driver further as suggested by Christoph Hellwig
- avoid some ifdefs by moving compat_ptr() out of asm/compat.h
- split out the blkdev_compat_ptr_ioctl function; bug spotted by
  Ben Hutchings
- Improve formatting of documentation

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 89 insertions, 25 deletions

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index bbd71af00a91..765bec89fc0d 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -300,11 +300,11 @@ void i915_request_retire_upto(struct i915_request *rq)
 }
 
 static int
-__i915_request_await_execution(struct i915_request *rq,
-			       struct i915_request *signal,
-			       void (*hook)(struct i915_request *rq,
-					    struct dma_fence *signal),
-			       gfp_t gfp)
+__await_execution(struct i915_request *rq,
+		  struct i915_request *signal,
+		  void (*hook)(struct i915_request *rq,
+			       struct dma_fence *signal),
+		  gfp_t gfp)
 {
 	struct execute_cb *cb;
 
@@ -341,6 +341,8 @@ __i915_request_await_execution(struct i915_request *rq,
 	}
 	spin_unlock_irq(&signal->lock);
 
+	/* Copy across semaphore status as we need the same behaviour */
+	rq->sched.flags |= signal->sched.flags;
 	return 0;
 }
 
@@ -811,31 +813,21 @@ already_busywaiting(struct i915_request *rq)
 }
 
 static int
-emit_semaphore_wait(struct i915_request *to,
-		    struct i915_request *from,
-		    gfp_t gfp)
+__emit_semaphore_wait(struct i915_request *to,
+		      struct i915_request *from,
+		      u32 seqno)
 {
 	const int has_token = INTEL_GEN(to->i915) >= 12;
 	u32 hwsp_offset;
-	int len;
+	int len, err;
 	u32 *cs;
 
 	GEM_BUG_ON(INTEL_GEN(to->i915) < 8);
 
-	/* Just emit the first semaphore we see as request space is limited. */
-	if (already_busywaiting(to) & from->engine->mask)
-		goto await_fence;
-
-	if (i915_request_await_start(to, from) < 0)
-		goto await_fence;
-
-	/* Only submit our spinner after the signaler is running! */
-	if (__i915_request_await_execution(to, from, NULL, gfp))
-		goto await_fence;
-
 	/* We need to pin the signaler's HWSP until we are finished reading. */
-	if (intel_timeline_read_hwsp(from, to, &hwsp_offset))
-		goto await_fence;
+	err = intel_timeline_read_hwsp(from, to, &hwsp_offset);
+	if (err)
+		return err;
 
 	len = 4;
 	if (has_token)
@@ -858,7 +850,7 @@ emit_semaphore_wait(struct i915_request *to,
 		 MI_SEMAPHORE_POLL |
 		 MI_SEMAPHORE_SAD_GTE_SDD) +
 		has_token;
-	*cs++ = from->fence.seqno;
+	*cs++ = seqno;
 	*cs++ = hwsp_offset;
 	*cs++ = 0;
 	if (has_token) {
@@ -867,6 +859,28 @@ emit_semaphore_wait(struct i915_request *to,
 	}
 
 	intel_ring_advance(to, cs);
+	return 0;
+}
+
+static int
+emit_semaphore_wait(struct i915_request *to,
+		    struct i915_request *from,
+		    gfp_t gfp)
+{
+	/* Just emit the first semaphore we see as request space is limited. */
+	if (already_busywaiting(to) & from->engine->mask)
+		goto await_fence;
+
+	if (i915_request_await_start(to, from) < 0)
+		goto await_fence;
+
+	/* Only submit our spinner after the signaler is running! */
+	if (__await_execution(to, from, NULL, gfp))
+		goto await_fence;
+
+	if (__emit_semaphore_wait(to, from, from->fence.seqno))
+		goto await_fence;
+
 	to->sched.semaphores |= from->engine->mask;
 	to->sched.flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN;
 	return 0;
@@ -980,6 +994,57 @@ i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence)
 	return 0;
 }
 
+static bool intel_timeline_sync_has_start(struct intel_timeline *tl,
+					  struct dma_fence *fence)
+{
+	return __intel_timeline_sync_is_later(tl,
+					      fence->context,
+					      fence->seqno - 1);
+}
+
+static int intel_timeline_sync_set_start(struct intel_timeline *tl,
+					 const struct dma_fence *fence)
+{
+	return __intel_timeline_sync_set(tl, fence->context, fence->seqno - 1);
+}
+
+static int
+__i915_request_await_execution(struct i915_request *to,
+			       struct i915_request *from,
+			       void (*hook)(struct i915_request *rq,
+					    struct dma_fence *signal))
+{
+	int err;
+
+	/* Submit both requests at the same time */
+	err = __await_execution(to, from, hook, I915_FENCE_GFP);
+	if (err)
+		return err;
+
+	/* Squash repeated depenendices to the same timelines */
+	if (intel_timeline_sync_has_start(i915_request_timeline(to),
+					  &from->fence))
+		return 0;
+
+	/* Ensure both start together [after all semaphores in signal] */
+	if (intel_engine_has_semaphores(to->engine))
+		err = __emit_semaphore_wait(to, from, from->fence.seqno - 1);
+	else
+		err = i915_request_await_start(to, from);
+	if (err < 0)
+		return err;
+
+	/* Couple the dependency tree for PI on this exposed to->fence */
+	if (to->engine->schedule) {
+		err = i915_sched_node_add_dependency(&to->sched, &from->sched);
+		if (err < 0)
+			return err;
+	}
+
+	return intel_timeline_sync_set_start(i915_request_timeline(to),
+					     &from->fence);
+}
+
 int
 i915_request_await_execution(struct i915_request *rq,
 			     struct dma_fence *fence,
@@ -1013,8 +1078,7 @@ i915_request_await_execution(struct i915_request *rq,
 		if (dma_fence_is_i915(fence))
 			ret = __i915_request_await_execution(rq,
 							     to_request(fence),
-							     hook,
-							     I915_FENCE_GFP);
+							     hook);
 		else
 			ret = i915_sw_fence_await_dma_fence(&rq->submit, fence,
 							    I915_FENCE_TIMEOUT,